This article analyzes the spatial-geometric properties of polyhedra and the theoretical foundations of their intersection with a plane. The definition of a polyhedron, its main elements (faces, edges, vertices), and its types are scientifically explained using examples of prisms, pyramids, and regular polyhedra. The property that the cross-section formed by intersecting a convex polyhedron with a plane is itself a convex polygon is substantiated through geometric and analytical approaches.

Polyhedron, plane, cross-section, convex polyhedron, spatial geometry, stereometry, prism, pyramid, regular polyhedron, analytic geometry, plane equation, intersection point, geometric modeling.

Yodgorov, J. *Chizma geometriya* [Descriptive Geometry]. - Tashkent: O'qituvchi, 2018. - 232 pages. (Chapter on polyhedra and their intersection with a plane, pp. 100-120).

Solihov, S.S., & Karimov, A.A. "Muntazam ko'pyoqlar kesimlari" [Cross-sections of Regular Polyhedra]. - *IJODKOR O'QITUVCHI*, 2025, Vol. 4, No. 47. - pp. 15-22 (abstract and introduction on pp. 15-16).

"Cross section (geometry)." - Wikipedia, "Cross section of polyhedron" section (accessed: 2026).

"Ko'pyoqlarning tekislik bilan kesilishi va uning yoyilmasini yasash" [The Intersection of Polyhedra with a Plane and the Construction of its Net]. - Term paper, 2024. - pp. 10-18 (algorithmic construction methods).

Khojamov, Z. S. (2021). "Problems of modeling on the subject 'drawing geometry and engineering graphics'." *World Bulletin of Social Sciences*, 5, 90-91.

Khujamov, Z. S., & Saparov, Kh. R. (2023). "Formation of Graphic Literacy of Requirements in Drawing Lessons." *Journal of Intellectual Property and Human Rights*, 2 (3), 24-26.

Khojamov, Z. S. (2021). Models of Computer Graphics of Special Curved Lines Lying on a Curved Surface. European Journal of Agricultural and Rural Education, 2 (12), 85-88.